Electrical indicator.



no. 6343187. Patented oct. mi, |399.

M. lwmzmzu., E'LELKTRICAL INDIGATUB.

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u. 634,487.. Patenten ont. lo, 1899.

M. WADDELL.

ELECTRICAL INDICATOR.

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UNITED STATES PATENT 'OFFICE- ELECTRICAL vHNlDlCATORl SPECIFICATION forming part'of Letters Patent No. 634,487,6.ated October Application filed January 10, 1899. Serial No. '701,697 (No model.)

To au whom, t may :Jo/werft:

Be it known that I, MONTGOMERY WAD; DELL, a subject of the Queen of Great Britain, residing at the' city of New York, in the borough of Manhattan and State of New York, have invented certain new and useful luiprovements in Electrical Indicators, of which the following is a full, clear, and exact description.

This invention relates to electrical indicators or instruments whose function is to show at any time the condition of the current flow? ving in an electric circuit or circuits.

The object of the invention is to provide an instrument of.' this character in which there shall be, practically speaking, no movement of solidV masses created directly by the current, thus eliminating at once many problems and diiiculties which have hitherto proved to be obstacles to the production ot accuratelyoperatinginstruments. In thoseinstruments containing moving parts the weights of those parts, their inertia, the friction accompanying their motion, tbc., must be allowed for, and with the changes Wrought in such parts by differences in `temperature it is quite difticult to construct such instruments to more In the instrument I have invented there is, in theory, a moving part, but the motion is so slight, in' fact, that it can scarcely be detected by the naked eye and is negligible as a factor in the production of an accurate instrument. The indicating element of the instrument herein described is a column of liquid ,which is caused to rise and fall by diereuces of gas or air pressure, which differences are created in accordance with variations in the current whose condition is being indicated.

My improved indicator comprehends important details of construction, as well as certain novel and important principles, all ot which will befully described hereinafter and pointed out in the claims. f

In the accompanying drawings, Figure l is a vertical sectio'n through a switchboard or other support, showing the instrumentin side elevation. l Fig? is'a verticalicentral section of the instrument with parts in elevation and other parts broken out. Fig. 3 is a plan of the base-plate supporting the magnet and controlling devices. Fig. l is a plan ot' the under large chamber.

side of the magnet. Fig. 5 is a section on line a; o: of Fig. 2. Fig; G is a plan of the disk containing the air-escape ports. f

Referring to the drawings by letter, let A representa slab of slate or other material constituting the facepf a station-switchboard or other adopted support for the instrument.

In front of this and extending vertically is a glass tube o, similar to a gage-glass, supported between upper and lower couplings bf b2, respectively, and carrying a plate b3,u ponwhch a suitable scale is marked. A tube from the upper coupling extends through thesupport A into the base-plate C of a ldome C, while the lower coupling similarly connects through the plate A with the lower end ot'v a ,stand pipe B, whose upper end, for purposes of stability only, is attached to the under side of the base-plate O. The stand-pipe and gageglass contain water, oil, or other liquid, preferably colored to be easily observed in the glass and freely communicating through the lower coupling. The capacity of the standpipe compared with that of the gage is large,

so that a-displacement of the liquid in the y gage will be accompanied by only a slight displacement of the liquid inthe stand-pipe. The atmosphere is freely admitted above the liquid in the stand-pipe through suitable openings in the upper end of the latter.

Referring now to Fig. 2 forV theconstruction of the baseplate C', it will' be observed that the plate is of considerable thickness and containing a central internal passage c, extending from front to rear. At the front this passage connects with the passage through the tubular coupling b'. From this coupling it extends rearwardly to about the middle point of the plate, where it enlarges into a threaded cylindrical chamber of short length and then widens into a large chamber extending to the rear of the plate, where it is sealed by a plug c. At the rear and passing upward from the under side of the base-plate are two conical passages c2 c2, leadinginto the These are adapted to receive pipe-couplings, one of which connects by suitable tubing with a source of constant air or gas pressure, while the other may be plugged up or connected with another tube leading to another indicating instrument of a similar character, thereby providing for connecting ICO a series of the instruments with the same source of air-pressure and insuring tha-t the pressure in all the instruments will be practically the same, since the air-chambers of each are connected together. The intermediate or threaded portion of the air-chamber receives athreaded plug e, having a tailpiece e', extending rearwardly nearly the entire lengt-h of the larger portion of the air-chamber, at which point it is fitted with a head adapted to receive a screw-driver, whereby it may be screwed into place in the threaded opening described and cut off communication between the front and rear portions of the passage c. This'plug c has an axial passage e2 extending through its threaded portion only and in alinement at its forward end with the air-passage extending to the coupling b. Into the rear end of this passage c2 the end of a capillary tube e3 projects, a suitable opening being made in the plug to admit the end of the tube and wherein it is hermetically sealed. The capillary tube is some eight or ten inches long in the ordinaryinstrument, and in order to confine it in a small space it is coiled around the tailpiece e of the plug, its free or rear end being open to admit the air in the chamber into it, whence it flows through passage e2 in the plug and into the forward portion of the passage or chamber c. Atfis shown a vertical threaded passage extending from the chamber c upward through the face of the base-plate. Into this is screwed a plug g, having an enlarged cylindrical head g', slightly cup-shaped on its Vupper surface, into the cavity of which is fitted a disk g2. The disk does not extend entirely to the bottom of the cavity in the plug, a space being left under it to serve as an air-chamber. This air-chamber communicates with the passage or chamber c in the base-plate through a restricted axial passage g3 in the plug. The disk is provided with a series of very restricted or capillary vertical passages g, arranged in a circle near its edge, the upper side lof the disk 'having short nipples, through which these passages, respectively, lead. The upper surfaces of these nipples are trued off, so that a perfectly-smooth plate resting upon them would prevent the escape of air from the chamber beneath the disk and so from those passages with which the chamber connects. Resting upon this circle of nipples is a vspool t', carrying a coil of wire e", the axis of the spool being coincident with that of the disk beneath it and .the end surface of the spool being provided with an accuratelyformed flat smooth face to insure uniform contact with all of the nipples and a consequent accurate control of the escape or flow of air therethrough. The two terminals of the coil t" connect, 1espectively,\vith metallic bent fingers i2 i3, which lead from the spool and turn down into mercury contact-cups j. These cups are formed or attached to the ends of binding-posts and pass through the baseplate, being suitably insulated therefrom by the bushings j' and provided with clampingnuts, to which the electrical conductors conveying the current whose condition is to be indicated arerespectively connected. v

Arranged above the base-plate is a permanent magnet M, consisting of an inverted, U-shaped piece m of magnet-steel and a fiat cross-piece m of gray iron, rigidly attached to one of the arms of the U-shaped part by the screws m2 and extending thence toward and beyond the other arm thereof. In the free end of the part m a vertical circular opening mSis formed, through which projects the free arm of the part m, it being made cylindrical for this purpose and of smaller diameter than the opening to'leave an annular armature-space between thetwo poles of the magnet. The extremity of the pole of the part m is flush with the under surface of the part in'. This magnet structure is supported upon the base-plate C by means of brass spacing-studs it', which pass through ears in the part m of the magnet and into the solid metal of the base-plate, thus furnishing a rigid and magnetically-insulating support for the magnet.

The spool i and its coil of wire 2'/ occupy the annular armature-space of the magnet, while the bent arms projecting into the mercury-cups pass out laterally through grooves m5, formed on the under side of the part fm.

The operation is as follows: Let it be understood that a pump or reservoir is furnishing gas or air under approximately uniform pressure to the rear end of the chamber or passage c through one of the-openings c2. This air or gas slowly forces its way through the capillary tube into the forward end of passage c, through the coupling b, and acts upon the surface of the liquid in the glass column, forcing the liquid down to a point depending upon the effect-ive pressure of the air at the surface of the liquid. This point is predetermined as the zero-point of the scale, and the liquid in the glass column will always be at this poi-nt so long as no current iiows through the coil i. At the zero-point the vupward pressure of the liquid exactly balances the pressure of the air. It may be stated here that the air inthe forward portions of chamber or passage c is, practically speaking, always subject to some 'leakage through the valve, the amount of such leakage when no cu-rrent is liowing being dependent upon the size and weight of the valve and the pressure of air. This fact -will therefore be a factor in fixing the Zero-point of the scale. Now when the current whose condition as to strength, tre., is to be indicated is turned on it flows through the coil fi in such a direction that when acted upon by the lines of force of the magnet M, concentrated in the armature-space, the tendency will be to lift `the coil and its spool and uncover the nipples ofthe valve, so permitting the escape of air from the chamber c, thus reducing the pressure upon the liquid TOO IIO

Thus the liquid column will always indicate the condition of the current flowing.

Now while I have referred tolthe movements ofthe coil and its spool as a lifting-and- .falling operation the fact is that these move ments are so slight that they not only can scarcely be detected by the naked eye, but

require an extremely delicate instrument to measure them. Perhapsthe best description of the operation of the'airfvalve is to say4 that the spool is caused torest lighter or heavier lupon the nipples, according as the current flowing through its coil is stronger or weaker. From' a practical standpoint the spoolk does not break contact with the nipples, but in theory and in fact there is a tilm of air between the end of the spool and-the surfaces of the nipples in thickness depending upon the strength of the current.

The function of the capillary tube e2 is'to Aact as a retarding device for the air between kthe source of air-pressure vand the air-chamber whose pressureis controlled by the airvalve The capillarytube being of verysmall vdiameter offers a high resistance to the ilow of the air from the rear toV the forward portions of the chamber c, and if ,an Vextraordinarily large amount of air be released from the forward par-tof said chamber by the valve nearly its entire effect will be felt bythe liquid column,instead of a material port-ion of the eect being wasted in drawing air from lthe rear part -ot' the passage c, connected .di- -rectly with the source of air. This 'capillary tube also acts as a damper between the surface' of the liquid column and the source, of airfpressure, the sudden eect of impulses of airbeingthereby reduced. The function of the capillary tube being understood, it becomes obvious at once that other devices may l,he'substitnted for it. Hence my invention comprehends any construction of air-flow resistance. f Y The principle of. this indicator isadapted -for'use in various ways. For instance,the`cur rent may be sent through the coil inthe op-v posite direction, whereat increase of current through the coil would have the tendency to Vlower the spool or make it rest more heavily upon the nipples, which would give an increased air-pressure and a' lowering of the liquid column. When operated in this way, the zero-point would have to be at the top of the liquid column, and the air-pressure at zero would be equ al to the atmosphere. Again the zero-point of the scale may be vat an iuunder pressure in this instrument Aforce of the magnet in the small armaturelevel of a liquid column by the lflow 'of air or termediate point of the column, so that when the instrument is used on a circuit in which the direction of current reverses, such as a storage-battery circuit, the discharging-curr 7o rent would be indicated oirthe scale above the zero-mark, due to the decrease of air-pressure, while thechargingcurrent, which would be in the opposite direction, would be indicated on the scale below the zero-point, due to increase of air-pressure.

There are other ways of utilizing air or gas without modifying its general construction. Ther drawings illustrate a dome C covering the 8o magnet and valve mechanism. When the air flows out of the chamber c through the valve to the atmosphere, this dome merely serves to protect the apparatus from dust and injury and will be provided at some point with a small hole to permit the escaping'air to ilow out' and avoid back pressure. This dome, however,maybe hermetically sealed and a suction-pump applied to it to exhaust the air therefrom 'and maintain a vacuum. Then by admitting atmospheric or any other pressure at the point c2 the operationof the instrument will be substantially. the.. same as before, except that the air will .be 'drawn through the valve instead of forced through it. In either case there is a difference of pressure on the opposite sides of .the valve, and this difference, which is controlled by the valve, determines the level of the liquid colf umn. It may alsobe mentioned that the at mosphere maybe excluded from the space above the liquid in the stand-pipe at the rear, in which event the gas-pressure on the in'dicating-column would be resisted only bythe dierenceA in weight of the two columns. That portion of the invention which relates to the altering of air or gas pressure in accordance with variations in the current may IOO ' be supplied in an instrument whose indicating element is other than a liquid column-as, for 1 [o instance, an ordinary air or'gas pressure gage with an index. i The object in using the cross-piece m' of the magnet is to concentrate all the lines of space occupied by the coil. I am thereby able to use less power in the coil and a small` light spool. By the use of the mercury contacts the movements of the spool are not interfered with. Itis obvious that the main features of this instrument could be used in electrical meastiring or recording instruments. Hence the claims herein are not limited in scope to electrical indicators. l The use of the word air7 in the claims is intended to cover any duid medium suitable for'the purpose.

Having described my invention, I clainrl. The. method of operating electrical indicators, which consists in determining the' gas, and varying said ilow in accordance with the variations of current.

2. In an electrical indicator, the combination of means for maintaining a diierence of fluid-pressure, an indicating element sub- 'jected to said difference of fluid-pressure and dtion of a column of liquid whose level indicates thecondition of the current flowing, an air-supply acting upon the liquid to change its level, and means whereby the electric current varies the pressure of the supply of air, substantially as described.

a. In an electrical indicator, the combination of af column lof liquid whose level indicates the condition of the current flowing, an air-supply acting upon the liquid to change its. level and a valve controlling the pressure of the supply of air saidv valve being operated by variations in the current flowing, substantially as described.

5. In an electrical indicator, the comb-ination of a column of liquid whose level indicates the condition of the current flowing, an air-supply acting upon the liquid to change its level, a valve controlling the pressure of the supply, a coil of wire through which the indicated current flows, a magnetic field of force in which said coil is located, said valve being controlled by the movements of said coil substantially as described.

G. In an electrical indicator, the combination of an indicating element, an air-supply actuating the same and means whereby the electric current varies the pressure of the air supplied, substantially as described.

7. In an electrical indicator, the combination of an indicating element, an air-supply actuating the same and a valve controlling the pressure ofthe supply of air, said valve being operated by variations in the current -flowing, substantially as described.

8. In an electrical indicator, the combination of an indicating element, an air-supply actuating the same, a valve controlling the pressure of the supplied air, a coil of wire through which the indicatedcurrent flows, a magnetic field of force in which said coil is located, said valve being controlled by the movements-of said coil, substantially as described.

9. In an electrical indicator, the combination of an indicating element, an air-supply actuating the same, and an air-flow resistance through which the air passes, substantially as described.

l0. In an electrical indicator, the combination of an indicating element, an air-supply actuating the same, an air-flow resistance through which the air passes and a pressurecontrolling device actuated by the indicated current and acting upon the air between the air-flow resistance and theindicating element, substantially as described.

ll. In an electrical indicator, the combination of a column of liquid whose level is the indicating element, a source of air-pressure acting upon the liquid to change its level, an air-ilow resistance between the air source and the liquid, and an air-escape valve controlled by the current and located between the controlling device andthe liquid, substantially as described.

l2. In an electrical indicator, the combination of an indicating element, an air-supply actuating the saine, a capillary tube through which the air passes and a pressure-controlling device actuated by the indicated current and acting upon the air between the capil lary tube and the indicating element, substantially as described.

13. In an electrical indicator, the combination of an indicating-column ofliquid,asource of air-pressure acting upon said liquid, a capillary tube through which the air passes to reach the liquid column, and an electricallyoperated air-escape valve located between the capillary tube and the liquid, substantially as described.

ll. In an electrical indicator, the combination of a U'shaped tube containing a liquid, means for admitting air under pressure against the surface of the liquid in one leg of f the tube, and an electrically-controlled valve for adjusting the air-pressurel5. In an electrical indicator, the combination of air under pressure controlling the indicatin g element, a valve controlling the pressure of air, said valve consisting of a disk having a series of perforations through it, and a cover-plate resting upon the disk and closing said perforations and adapted t0 be moved by the current whose condition is-being indicated.

lG. In an electrical indicator, the combi-nation of air under pressure controlling the indicatin g eleinen t, a valve controlling the pressure of air, said valve consisting of a'disk having a series of perforations through it and arranged in a circle, a spool carrying a coil through which the indicated currentilows and which is subjected to the iniluence of a magnetic field, said spool carrying a ilat circular surface adapted to impinge upon said disk to control the perforations therein, substantially as described.

17. In an electrical indicator, the combination olf-an indicating element consisting of a U-shaped tube, the legs of which are of different diameters or capacities and contain a liquid, and electrically-operatedmeans for changing the level'of the liquid in the smaller leg, substantially as described.l

In Witness whereof I subscribe my signature in presence of two witnesses.

MONTGOMERY IVADDELL. Witnesses: l

WM. A. ROSENB'AUM, FRANK S. OBER.

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